The ability to measure range to a reflecting object by using the parallax effect has been used extensively in environmental sensing. However, current and previous generations of technology used to perform such range measurements generally rely upon multiple imagers and/or multiple satellites to achieve a diversity of views as required for such measurements. The cost and complexity of such systems has therefore been undesirably high. To address some of these drawbacks, solutions have been sought in the area of range measurement technology and prototypes have been built and flown to demonstrate new technologies.